NATURE29 May 2023

ByTESSA KOUMOUNDOUROS

(Wirestock/Getty Images)

https://www.sciencealert.com/marsupials-are-far-more-evolved-than-other-mammals-even-humans

A new study challenges the idea that marsupials are more ‘primitive’ than mammals by showing their development has changed more than mammals since they last shared an ancestor.

https://3dee7b1d64d93b400ab3f8c4cb345497.safeframe.googlesyndication.com/safeframe/1-0-40/html/container.html

“For a long time, people have treated marsupials as ‘lesser mammals,’ which represent the intermediate stage between placental mammals and egg-layers,”explainsevolutionary biologist Anjali Goswami from the Natural History Museum in the UK.

“It turns out that marsupials are the ones that are far more evolved from the ancestral form.”

This now outdated idea arose from the fact that marsupials, such as kangaroos, give birth to young still in the early stages of development. This leaves their babies to do most of their development within pouches, seemingly a step more complicated than what egg-laying monotremes like platypi do, yet still simpler than placental mammal development.